Knife

ABSTRACT

A power actuated knife with a single blade attached to a free end of a support, the other end of the support being attached to the handle. One end of the motor casing is attached to the handle through a vibration absorbing bearing and the motor at the other end has a rotatable oscillating connection to a bracket which engages the support at a location removed from its attachment to the handle whereby an oscillating sinusoidal motion is applied to the blade through the support to set the entire blade in motion.

0 Muted States Patent [151 3,664,021 Sawyer May 23, 1972 KNIFE 3,359,63712/1967 3416398 12/1968 2 l 1d [7 nventor Haro T Sawyer, PacificPalisades, Calif 3,468,384 9/1969 [73] Assignee: Vernon D. Beeler, LosAngeles, Calif. a 3,316,428 4/1967 part interest [22] Filed: Oct 30,1969 Primary Examiner-Theron E. Condon Assistant Examiner-J. C. PetersPP ,690 Attomey-Beehler & Arant 52 us. Cl ..30/272, 83/6475, 173/49 [57]ABSTRACT [51] Int. Cl ..B26b 7/00 A power actuated k if with a Singleblade attached to a f [58] Field of Search ..30/272, 273, 169; 146/203,end ofa Support, the other end f the support being attached 146/204;83/523 6 74/42; 173/49; 310/51 to the handle. One end of the motorcasing is attached to the handle through a vibration absorbing bearingand the motor at [56] References cued the other end has a rotatableoscillating connection to a UNITED STATES PATENTS bracket which engagesthe support at a location removed from its attachment to the handlewhereby an oscillating sinusoidal 2,320,784 6/1943 Livingston ..30/272motion is applied to the blade through the Support to set the 2,958,35511/1960 Young ....30/272 X entire blade in motion 2,984,005 5/1961 Evich....30/272 3,052,981 9/1962 Landes ..30/272 9 Claims, 10 Drawing Figuresfull KNIFE As power actuated knives have become available on the market,virtually all have uniformly followed a design which incorporates twoblades mounted side by side in engagement with each other, both of whichare provided with edges which can aptly be described as saw-tooth edges,the blades being driven in such fashion that they move relative to eachother so as to cut through the object with a sawing motion. Aconstruction of the kind described requires an appreciable amount ofmotor power sufficient to move at least one of the blades, and oftenboth of them, lengthwise for an appreciable distance at the end of whichmotion must be stopped and then reversed. Reciprocating motion of thiskind consumes a considerable amount of power because at everyreciprocation the moving blade must be brought to a stop and thenstarted in the opposite direction. Appreciable mechanism is required inorder to transmit motion from an electric motor to the moving blade andto adjust its speed relative to the normal speed of the motor so that atleast one blade, and usually both blades, are moving at a desirable rateof speed. Obviously also, the blades must be confined one against theother so that their adjacent surfaces are in engagement since otherwisethe cuttings and debris would accumulate between the blades andinterfere with their proper motion. The problem is also present ofconfining the ends of both blades by means of which they are mounted ina position close together but still capable of being driven separately,and also requiring that they be mounted in such fashion that both ofthem can be removed after use for washing, drying and then replacement.The construction inherently needed for an apparatus of the kinddescribed must be heavy because of the requirement for two blades stiffand rigid enough to be mounted and handled as described and also mountedin a handle big enough to accommodate a relatively powerful motornecessary to drive them.

Among the objects of the invention is to provide a new and improvedpower actuated tool which may be a knife blade or other comparableinstrument whereby only a single blade is made use of mounted andoperated in such fashion that rapid bending wave movement of the bladewith a frequency comparable to the low sonic range is made use of invastly increasing the ability of the blade to do the work it wasdesigned for.

Another object is to provide by design a maximum and most efficientworking tool with a minimum source of input energy.

Another object of the invention is to provide a new and improved poweractuated tool which makes use of a single blade assembly mounted incantilever fashion in a handle which also houses the motor, the assemblybeing such that a sinusoidal force generated in the motor is applied tothe blade or a cantilever beam which supports it at a location removedfrom its resilient mounting, whereby to generate bending wave motions ofvibration which are made use of to enable the blade to do its intendedwork.

Another object is to excite the blade tool member at bending wave motionspeeds approaching 250 cycles per second as compared to 30 cycles ofconventional electric knife motion speeds.

Another object of the invention is to perform physical work by excitinga bending wave force motion in the blade and thus causing a frequencydeflection of the blade.

Still another object of the invention is to provide a new and improvedpower actuated knife which makes use of only a single cantilever mountedblade, the blade being removably attached to a cantilever-like mountingso that is can be removed for cleaning and replaced when needed, themotor power being applied to the mounting at a location within thehandle housing so that the device is always ready for operation as soonas the blade is attached.

Still another object is to provide by design a system structure capableof functioning at or near its natural frequency so that maximumamplification of a power source can be achieved from a minimum inputsource,

Still another object of the invention is to provide a new and improvedpower actuated knife consisting of a single blade mounted in cantileverfashion in a handle which houses the source of motor power, thestructure of the device as a whole being such that the moving parts actin resonance when power is applied to the blade.

Also included among the objects of the invention is to provide a new andimproved power actuated single blade electrically operated knife whichis extremely simple and inexpensive in its construction and assembly andwhich is especially effectiveas a cutting instrument.

With these and other objects in view, the invention consists in theconstruction, arrangement, and combination of the various parts of thedevice,whereby the objects contemplated are attained, as hereinafter setforth, pointed out in the appended claims and illustratedin theaccompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of the device showing the blade inplace and ready for operation.

FIG. 2 is a longitudinal sectional view of the device.

FIG. 3 is a cross-sectional view of the blade on the line 3-3 of FIG. 2.

FIG. 4 is a cross-sectional view of the blade mounting on the line 44 ofFIG. 2.

FIG. 5 os a fragmentary sectional view on the line 5-5 of FIG. 2.

FIG. 6 is a fragmentary sectional view on the line 6-6 of FIG. 2.

FIGS. 7 and 8 are schematic views of the blade showing different blademovements to which it is subjected.

FIGS. 9 and 10 are motion line diagrams.

In an embodiment of the invention chosen for the purpose of illustrationthere is shown a housing 10 which serves simultaneously as a handle andas a housing for the motor and its attachment to a tool, herein takingthe form of a knife blade 11. Within the housing 10 is a pocket 12 inwhich is a rechargeable battery 13 and a chamber 14 within which is anelectric motor 15, the motor being interconnected with the battery in aconventional manner, not shown. Leads 16 and 17 of the rechargeablebattery 13 extend through a removable cap 18 so that the battery can beremoved for replacement. Springs 19 and 19 serve to hold the batterysnugly in position.

The electric motor is provided with a stub shaft 20 on a flange 20 bymeans of which the motor 15 is supported at one end only of the shaft ona partition 10' in the housing 10, the partition acting to separate thepocket 12 and the chamber 14. Mounting is accomplished by employment ofa vibration damping unit 21 held in place by means of a setscrew 22. Asshown in some detail in FIG. 6, a sleeve 23 and a shell 25 confinebetween them an isolation bearing mount 24 of shock absorbing material.

As will be noted, a bore 28 in the partition 10 accommodates the unit21, the annular shell 25 being contained firmly therein so that there isno prospect of engagement with the stub shaft 20 and the sleeve 23.

At the other end of the motor is a rotating motor shaft 33 and aneccentric bearing assembly indicated generally by the referencecharacter 30. The bearing assembly 30 consists of a bracket 31 withinwhich is rotatably mounted a bearing race 32 commonly known as a selfaligning ball bearing. Eccentrically mounted in the bearing race 32 isan eccentric bearing 34 which projects from the adjacent end of a stubshaft 36 confined in the bearing race 32, the motor shaft 33 beingmounted in the eccentric bearing 34.

A permanently located mounting member is provided with a post 35 securedin a vibration damping unit 37 similar to the unit 21. The unit 37 inturn is secured within a closed pocket 38 by means of a set screw 39.The mounting member 35 may be compared with a tuning fork in that themounting member 35 is free to move by reason of its inherent design. Themounting member 35 and the bearing assembly 30 are so connected to eachother by means such as screws 31' and they are in constant engagementwith each other as shown in FIG. 2. An outer end 40 of the mountingmember 35 extends outwardly through a soft rubber seal 41 mounted in aremovable plate 42 of the housing 10 whereby to effectively seal theinterior of a recess 43 and also the chamber 14 from the exterior. Theknife blade 11 has a butt end extension 44 which is removable attachedto the outer end 40 of the mounting member 35 by an appropriatereleasable connection 45.

In the chosen embodiment the connection 45 consists of a case 46 inwhich is a recess 47, wedge shaped in cross section, for reception ofthe butt end extension 44 which has also a wedge shape in cross section.A rotatable cam 48, manipulated by a handle 49 is adapted to force thewedge shaped parts together, thereby to releasably anchor the knife tothe mounting member 35.

The knife blade 11, except for a small section near the butt end 44, mayhave a somewhat razor blade shaped cross sectional configuration, asshown in FIG. 3, there being a back edge 50 relatively stiff and heavycompared to a tapered blade edge 51. The height of the blade also variesfrom relatively narrow to relatively wide, as shown in FIGS. 7 and 8.

In operation, when the tool is to be put to use, the blade 11 isattached to the outer end 40 of the mounting member 35 and the motor 15energized by means of a switch 53. As the motor shaft 33 is rotated bythe motor the end of the motor shaft mounted in the bearing race 32rotates so that the motor shaft 33, eccentrically mounted in theeccentric bearing 34 causes the bearing race to rotate relative to theeccentrically mounted motor shaft 33 thereby to impart sinusoidal motionto the bracket 31 at a rate depending upon the speed of rotation of themotor shaft 33. The sinusoidal motion set up in the bearing assemblybracket 31 is conveyed to the mounting member 35 and the blade 11 bydirect contact of the bracket with the mounting member. The outer end40, therefore, of the body of mounting member 35 is excited insinusoidal motion, while its attached end is held relatively motionlessby the unit 37. This sinusoidal motion is conveyed directly to the blade1 I and the blade correspondingly set in motion.

The forms of the motion imparted to the blade 11 are illustrated byFIGS. 7 and 8 in that there is movement in different directions. Forexample, as illustrated by FIG. 7 the blade 11, mounted as a cantileverbeam, is vibrated in a condition approaching resonance and moveshorizontally in the direction illustrated by the wave line illustration60. Actually, movement of the blade is ellipsoidal as indicated by theforce motion end view 61. Three-dimensional ellipsoidal force patternsare released by the resonating cantilever beam in the form of the blade11 in three planes. FIG. 8 shows vibration in the next higher mode, withmotion indicated by the wave line 60 and end view 61 There is asinusoidal driving force in the low sonic frequency range which bydesign is generated by the motor mass revolving at one end of that massabout its eccentric. That sinusoidal driving force is transmitted bymeans ofits supporting pedestal and bearing assembly to the mountingmember, the whole acting as a tuning fork structure capable of beingresonated with the cantilever beam structure embodied in the blade at adesired frequency and amplitude to do work commensurate with itsapplication. When the blade is a knife blade sharp on one edge, thatwork will be cutting. Should the blade be a pallet knife, the work willbe of some other kind. The device described performs work by means ofresonance excitation at a desired frequency. By inherent design at adifferent frequency the resulting motion is exemplified by FIG. 7, whereinstead of a fundamental mode as illustrated in FIG. 9 action will be ina second mode of resonance and the force motion end view 61 will varyslightly from that illustrated by the reference character 62. Again, byinherent design at still a different frequency as illustrated in FIG. 8a third mode of resonance may be induced in the blade 11 which will varythe force motion end view so that it will appear as represented by thereference character 61'.

To still further illustrate the motion of the blade 11 attention isdirected to FIG. 10 wherein at a 90 phase angle is depicted for thefirst mode of resonance comparable to FIG. 9, the illustration of FIG.10 being motion imparted to the blade in a direction toward and from itscutting edge, indicated at 63.

A typical operating example of the device is one wherein the sonicenergy source is embodied in a small 1.5 volt or 3 .00 volt cylindricalmotor of conventional construction and as illustrated by the motor 15.The mounting member 35 and outer end 40 which can effectively bedescribed as a tuning fork resonating beam. Although a separate bracket31 is shown, the bracket 31 and the mounting member 35 may beconstructed of a single piece of material of proper consistency, held inposition as described by the set screw 39. The connection between themounting member 35 and the blade 11 is a rigid connection so that allmotion imparted by the motor to the mounting member is conveyed directlyto the blade 11.

The right hand end ofthe motor 15 has a stub shaft 20 and is confined asshown within the sleeve 23 forming a construction such that the motorcasing is secured in the joint of FIG. 6 which may be described as aballjoint assembly permitting the motor shaft 33 to rotate radiallyrelative to the longitudinal motor axis. At the other end of the motor15 the shaft 33 is the output end for force generated by the motormounted in the eccentric bearing assembly 34 which generates force issinusoidal in nature, and the eccentric bearing assembly 34 beingrigidly attached, mounting member 35 acting as a cantilever resonatingbeam assembly is motion driven into resonance by means of the motor 15acting as a sinusoidal sonic energy source. The amplitude of the forceis in proportion to the product of the motor mass and its eccentricthrow at the bearing assembly 34. The resonating cantilever beamassembly is analogous to a plate beam or to a tuning fork, as previouslysuggested, and by proper design the resonating knife blade 11 may bedesigned to resonate freely at or near its own natural frequency at itsfirst mode of resonance if desired. Further, by proper design inaccordance with these principles, the knife may be so designed as toresonate in the second or, if preferred, in the third mode of frequencyresonance which represents respective resonance frequencies of severaltimes the fundamental driving force frequency, as previously madereference to in connection with FIGS. 7 and 8.

For example, should the fundamental frequency ofthe sonic energy sourcebe cycles per second, by intrinsic design the first mode of resonance ofthe cantilever knife constructed as shown could be 80 cycles per second.Depending on the work to be done, the cantilever knife beam could bemade to resonate at the second or third modes of any fundamental of thenatural frequency of the knife beam.

The sonic energy source, namely the motor 15, is sound wave isolated atthe right hand end as viewed in FIG. 2 where it is confined in the unit21, thus providing a resilient radial support means which preventslongitudinal sound waves from entering the housing structure 10, servingin turn as the hantile.

The mounting member 35, serving as described as a tuning fork structure,is also isolated by means of its inherent design configuration. Itshould be understood that sound waves released by a resonating tuningfork travel in a direction toward the tuning fork prongs, by analogy,where their maximum amplitude and energy is released. It is cleartherefore that the sound waves are not released or directed to thehandle support structure in an assembly of the type described. Theresonating cantilever knife beam and its supporting tuning forkstructure comprise a complete system. The masses and springs of thesystem are designed to produce a resonant frequency of the completesystem so that optimum conditions exist. The resonating cantilever beamand its supporting tuning fork mounting are in effect sounding bodies.When the cantilever beam is resonated at the point illustrated in FIG.9, the beam will be resonating as a whole and, at the same time, theremay be harmonics of the fundamental frequencies. The physical sinusoidalforce resonating movement of the cantilever beam blade and itsknife-like edge do in fact produce work when physically contactinganother surface such as a surface to be cut. The device therefore doeswork when it cuts through the surface contacted, the work beingperformed by means of frequency motion in the low sonic range.

The physical resonating free movement of the cantilever knife beam isproduced by longitudinal bending and sound waves which are initiated bythe sound and energy source. When in resonance, the sinusoidal forcemotions are at a maximum, ellipsoidal in character, and are produced ineach of the three planes of the cantilever beam.

The physical cutting forces at the knife edge of the resonating bladeare derived from the longitudinal bending wave motions of the materialin the resonating cantilever beam. The forces are three-dimensional innature and ellipsoidal in structure. The physical cutting thereforetakes place at the knife edge when contacting another surface by meansof alternate three-dimensional force motion envelopes which are inplanes parallel and perpendicular to the surface of the material beingcut. it is the frequency and amplitude of the longitudinal sound andbending wave which sets up the resultant sound and bending wave throughthe resonating cantilever blade acting as a beam does in fact approach1,100 feet per second in velocity. The foregoing explanation is believedamply warranted in view of the simplicity of the device, consisting atit does of a single blade, and the special effectiveness with which itperforms. It will be appreciated from the explanation that the device isa composite unitary assembly the parts of which are so designed thatthey complement and enhance each other, to the end that a vibratorycondition exists at or near the peak resonance curve when the device isin operation, and in this way enhances its effectiveness undercircumstances where consumption of power is at a virtual minimum. As aconsequence, the device is particularly light in weight in proportion tothe work done.

lclaim:

l. A power actuated tool comprising a housing, a motor device having aresilient bearing mounting at one end only in said housing, a toolhaving a resilient bearing mount at one end mounted in said housing anda free end extending clear of said housing, and a sinusoidal forcemotion drive connection between said motor and said tool at a locationon said tool intermediate said free end and said one end, said driveconnection comprising a motor shaft on said motor, an eccentric memberconnected to and driven by said motor shaft and a connection betweensaid eccentric member and said tool.

2. A power actuated tool as in claim 1 wherein the tool is a knifemember and wherein said mounting comprises a resilient block with saidknife member mounted as a cantilever beam and said sinusoidal forcemotion drive connection is in an edgewise direction relative to a sharpedge of said knife member.

3. A power actuated tool as in claim 1 wherein there is a closed chamberaround said mounting for the tool and a yieldable seal around a portionof said tool extending outwardly from the housing.

4. A power actuated tool as in claim 3 wherein the tool has a mountingpart located in said closed chamber and extending outwardly therefromthrough said seal, and a working part having a removable connection tosaid mounting part at a location exterior relative to said housing.

5. A power actuated tool comprising a housing, a motor device mounted insaid housing, a tool having one end mounted in said housing and a freeend extending clear of said housing, and a sinusoidal force motion driveconnection between said motor and said tool at a location on said toolin termediate said free end and said one end, said drive connectioncomprising a motor shaft on said motor, an eccentric member connected toand driven by said motor and a connec tion between said eccentric memberand said tool, said motor having a single resilient mount at one endmounting said motor on the interior of said housing and wherein saidforce motion drive connection is at the other end of the motor.

6. A power actuated tool as in claim 5 including a rechargeable batteryand battery chamber in said housing in axial alignment with said motorand electric connections between said battery and said motor.

. A power actuated tool as in claim 1 wherein said housing has itsexterior in the form of a tool handle, and a switch on said housingconnected to said motor.

8. A power actuated tool as in claim 1 wherein the force motion driveconnection with said tool is a face to face pressure engagement andwherein said mounting for the tool is a resilient mounting biasing saidtool toward said pressure engagement with said drive connection.

9. A power actuated tool as in claim 1 wherein said isolation bearingmountings are omnidirectional.

1. A power actuated tool comprising a housing, a motor device having aresilient beAring mounting at one end only in said housing, a toolhaving a resilient bearing mount at one end mounted in said housing anda free end extending clear of said housing, and a sinusoidal forcemotion drive connection between said motor and said tool at a locationon said tool intermediate said free end and said one end, said driveconnection comprising a motor shaft on said motor, an eccentric memberconnected to and driven by said motor shaft and a connection betweensaid eccentric member and said tool.
 2. A power actuated tool as inclaim 1 wherein the tool is a knife member and wherein said mountingcomprises a resilient block with said knife member mounted as acantilever beam and said sinusoidal force motion drive connection is inan edgewise direction relative to a sharp edge of said knife member. 3.A power actuated tool as in claim 1 wherein there is a closed chamberaround said mounting for the tool and a yieldable seal around a portionof said tool extending outwardly from the housing.
 4. A power actuatedtool as in claim 3 wherein the tool has a mounting part located in saidclosed chamber and extending outwardly therefrom through said seal, anda working part having a removable connection to said mounting part at alocation exterior relative to said housing.
 5. A power actuated toolcomprising a housing, a motor device mounted in said housing, a toolhaving one end mounted in said housing and a free end extending clear ofsaid housing, and a sinusoidal force motion drive connection betweensaid motor and said tool at a location on said tool intermediate saidfree end and said one end, said drive connection comprising a motorshaft on said motor, an eccentric member connected to and driven by saidmotor and a connection between said eccentric member and said tool, saidmotor having a single resilient mount at one end mounting said motor onthe interior of said housing and wherein said force motion driveconnection is at the other end of the motor.
 6. A power actuated tool asin claim 5 including a rechargeable battery and battery chamber in saidhousing in axial alignment with said motor and electric connectionsbetween said battery and said motor.
 7. A power actuated tool as inclaim 1 wherein said housing has its exterior in the form of a toolhandle, and a switch on said housing connected to said motor.
 8. A poweractuated tool as in claim 1 wherein the force motion drive connectionwith said tool is a face to face pressure engagement and wherein saidmounting for the tool is a resilient mounting biasing said tool towardsaid pressure engagement with said drive connection.
 9. A power actuatedtool as in claim 1 wherein said isolation bearing mountings areomnidirectional.